Bat-inspired micro air vehicles in the offing

Friday, Feb 19, 2016,14:24 ISTBy Metrovaartha AAA

London | Researchers led by an Indian-origin scientist have designed innovative membrane wings inspired by bats, paving the way for a new breed of unmanned Micro Air Vehicles (MAVs) that can fly over long distances and are more economical to run.

The wings work like artificial muscles, changing shape in response to the forces they experience and have no mechanical parts, making MAVs incorporating them easier to maintain, said researchers from University of Southampton and Imperial College London in UK. The unique design of the wings incorporates electro-active polymers that makes the wings stiffen and relax in response to an applied voltage and further enhances their performance. By changing the voltage input, the shape of the electroactive membrane and therefore aerodynamic characteristics can be altered during flight.

The proof of concept wing will eventually enable flight over much longer distances than currently possible. Sometimes as small as 15 centimetres across, MAVs are increasingly used in a wide variety of civil and military applications, such as surveying remote and dangerous areas.

One emerging trend among MAV developers is to draw inspiration from the natural world to design vehicles that can achieve better flight performance and that offer similar levels of controllability to small drones but use the efficiency provided by wings to fly much further. Researchers focused on mimicking the physiology of bats – the only type of mammal naturally capable of genuine flight.

To inform and speed up the design process, they built innovative computational models and used them to aid the construction of a test MAV incorporating the pioneering ‘bat wings’. The findings were incorporated into a 0.5 metre-wide test vehicle, designed to skim over the sea’s surface and, if necessary, land there safely. After extensive wind tunnel testing, the vehicle was put through its paces at a coastal location.

We have successfully demonstrated the fundamental feasibility of MAVs incorporating wings that respond to their environment, just like those of the bats that have fuelled our thinking, said Bharath Ganapathisubramani from University of Southampton who led the study. We have also shown in laboratory trials that active wings can dramatically alter the performance.

The combined computational and experimental approach that characterised the project is unique in the field of bio-inspired MAV design, Ganapathisubramani said. Instead of a traditional approach of scaling down existing aircraft design methods, we constantly change the membrane shape under varying wind conditions to optimise its aerodynamic performance, added Rafael Palacios from Imperial College London.